Electric motor



Sept. 24, 1940. c DESOUTTER Re. ELECTRIC MOTOR Original Filed Oct. 15,1935 I H H. J

IIIl

Rea-ml p 2 .19 Re. 21,578

UNITED STATES PATENT OFFICE MC MOTOR Charles D uoutter, London, EnglandOriginal No. 2,045,219, dated June 23, 1986, Serial No. 45,148, October15, 1935. Application for reissue April 28, 1937, Serial No. 189,630. InGreat Britain November 2, 1934 13 Gllml. (Cl. 172-48) This inventionrelates to eilicient and readily ing comprises a main casing l, aremovable nose mounted electrical switching means for the elecor frontcap portion 8, which carries bearings tric motors of rotary tool devicescarried and for a tool chuck 9, and a removable rear end applied by handsuch as electric drills or the like. cover portion ll. Within the devicethere is 5 In general, according to the invention, the accommodated afield magnet Ii, field winding switching means is of the type comprisinga bobbin l2, an armature I! together with its as- -switching unitmounted in the body of the tool sociated commutator II and commutatorbrushes device, and is readily attached to or detachable II and I8,constituting a horse-shoe type motor. from the said tool device. It hasone or more Each side of the main casing 1 is provided contact-making orcircuit-completing devices with an aperture 1' into which is introduceda fixedly associated therewith and in connection switch box l1,constituted by two portions each electrically with the actual switchingmeans formed from insulating material and adapted to proper, which maybe of any suitable construcbe held together by means of screws indicatedat tion. ll (Figs. 2 and 3). It will be observed that the The motor hasco-operating contacts or cirswitch box ll extends from one side of thecasing cult-completing devices, which are so formed, 1 to the other sideand comes flush with the exdisposed or arranged that when the switchingterior thereof, whilst it also flts the approprimeans is attachedinposition, the contact-makately shaped apertures 'I' and is thus heldfrom ing or circuit-completing devices thereof register axial orvertical movements.

and make contact preferably by spring pressure To secure the switch boxin position the rear ll with the co-operating contacts orcircuit-comportion thereof is grooved at I! for the receppleting devicesof the motor. tion of an insulating cover 2| of the metal liner Thus,according to the invention, the switch- 2|, provided for housing thecommutator brush ing means with its contacts or the like, can be II. Thebrush holder thus, in effect, keys the as independently assembled andreadily can be box in position within the casing and when it 35 mountedor dismounted into or out of position. is in engagement with the groovel9, prevents the In this manner, the necessity for soldering or removalof the box. otherwise making connections from the switch A forwardextension of the groove is proto the appropriate circuit or circuits ofthe motor vides accommodation for the mounting of a me- 30 can beavoided and general assembly thus fatallic conducting member 22, aspring limb 23 80, cilitated; further, necessary repairs or replaceofwhich automatically contacts with the mements can be carried out withgreat expedition. tallic liner 2| when the brush holder is mounted Inorder that the invention may be fully unin position in the groove It.The member 22 derstood, it will now be more particularly dealso includesa spring limb 24 upon which is 35 scribed with reference to theaccompanying carried a contact pin 25, which extends through 86.drawing. .whereinv the wall of the box to project slightly into theFigure 1 shows a side elevational view, partly interior thereof. Thispin 25 constitutes one in section, of a hand-applied portable drillingpole of the switch device proper. tool, supported in the manner of apistol", which The front portion of the switch box also carincorporatesswitching means constructed and ries a metal conducting member, which isingo arranged according to a preferred embodiment dicated at 28. Thismember includes a spring of the invention. limb 21 towhich a contact pin28 is secured,

Figure 2 shows a front elevational view of the latter passing into theinterior of the box Fig. 1 with the upper part in section, the secat'a.position diametrically opposite that occupied 5 tion being takensubstantially on the line 2 2 by the pin 26 aforesaid. The pin 28constitutes 4g of Fig. l. the other pole of the switch device proper.

Figure 3 is a fragmentary sectional view taken within the interior ofthe box there is acon the line 3-3 of Figure 2. commodated manuallyoperable means for bridg- Figure 4 is a fragmentary sectional plan viewing the two contact pins 25 and 28, such means so ofaportion of Fig. 1and being conveniently comprised by a bifurcated so Figures 5 and '6show in elevation the inside element 29 which is formed from metal andhas of one portion of the switch box shown in the its forked endspivotally located by oppositely preceding figures-and the outside of theother disposed recesses 30 provided in the interior of portion of saidswitch box respectively. the box. v

as The particular t ol device shown in the draw- One side wall of thebox is slotted as at II to g EEE of the button '3: along the length slotIi willresultinacorresponding moveouter end of the forked element 2| temis mounted in position, applicant's co-pending patent application SerialNo. 45,148, filed October 15, 1935, patented June 28, 1936, Patent#2,045.218. Such automatlc contact-making is also eifected between afurther contact l'l carried by the bobbin it and a spring-influencedplunger contact 38 accommodated within a housing formed in the body ofthe switch box, said plunger contact being directly connected with aconducting lead 3! that passage ,and whose other end ried by a blockindicated at dotted lines in Fig. 1. A further terminal I! is alsomounted on the block. this latter terminal being arranged in electricalcontact with the commutator brush II.

A pair of conducting leads 4! from an electricalsupplyare adaptedtobeconnectedwith the terminals 4! and II.

'lhe sequence of electrical connections and contacts of the electricalsystem of the device are thus as follows: terminal 4l,-lead 3|,- plungercontact 38,-bobbin contact I'|,field winding,hobbin contact Il,springlimb 3',- contact pin 2l,forked element 29,-contact pin 2l,--spring limb13,-commutator brush ll,- armature windings,-commutator brush lt,-andterminal 42. 1

60 As an alternative to the direct connection of the lead 30 with theplunger contact II, a furtherplungercontactorspringlimbcarriedbytheswitch box and electrically connected with the plunger ll, could beprovided and adapted automaticaliy to make contact with a contactcarried by the casing of the device and to which the lead II isconnected, when the switch box is mounted in position.

Itistobeunderstood thatinsomecases spring limbs such as it and a, andplunger contacts such as II can be replaced by divided or other pins,sockets. metal plates or otherwise as desired, to make contact by springpressure.

Further, the electrical circuits of the motor may be as desired, and oneor more of the said circuits, according to the particular arrangement,may includes the switch proper. Consequently, the said circuit orcircuits of the motor is or are appropriately provided with cooperatingcontact or circuit-completing devices which are so formed, positioned orarranged that automatically when the switching means is located inposition. the appropriate circuit or circuits automatically arecompleted and remain casing, or a part thereof, may be formed the outerinsulated part of the latter is made in more than one means theelectrical connection the metallic part oi the brush holder proper maybe fixed, and in some located in working position. I

Where the switching means is more than unipolar, for example biortri-polar, it will be realised that the contacts carried by the casingthereof are correspondingly increased, and in some cases the necessityfor contacts not condircctly to the switch proper is obviated. inventionis not limited to the precise or details of construction described, asthese may be varied to suit particular cases.

What I claim and desire to secure by Letters Patent 01 the United Statesof America is:

1. A rotary tool device carried and applied by hand and incorporating anelectric motor, comprising a casing. a removable switch unit mounted ina recess in said casing, contact-making circult-completing. devices onsaid switch unit, cooperating contacts in said casing and in resilientengagement with the aforesaid contact-making or circuit-completingdevices, and means removably disposed in said casing to hold said switchunit in position therein.

2. A rotary tool device carried and applied by hand and incorporating anelectric motor, comprising a casing, a removable switching unit locatedwholly in said casing but provided with an operating member coming tothe outside of said casing, said switching unit including a housing ofinsulating material, a. movable switch element and fixed contactsengaged by said switch element, contacts on the exterior oi the housingof the switching unit, fixed contacts in said casing engagi saidcontacts on said switching unit resilientb, and means removably disposedin said casing to hold said switching unit in posi- Hon.

3. A rotary tool device carried and applied by hand and incorporating anelectric motor, comprising a casing having a transverse recess therein,a self-contained switching unit housed in said recess, said switchingunit including an operating knob coming to the outside of the casing anda groove in one side face thereof, contacts on the switching unit,corresponding contacts in the casing enga in the contacts on theswitching unit by spring pressure. and a member positioned radially tothe motor axis and engaging said groove in prevent lateral movement ofsaid switching unit in the casing.

4. A rotary tool device carried and applied by hand and incorporating anelectric motor, comnested The orms Y prising a casing having atransverse aperture therein. a self-contained switching unit removablymoimted in said aperture, said switching unit being provided with anoperating member coming to the'outside of the casing and having a grooveon one side face thereof, cooperating contacts on said wit and in saidcasing, said cooperating contacts engaging one another by springpressure, and brush holders in said casing, one of which is adapted toengage the groove in the switching lmit to hold same in position in theaperture in the casing.

5. A rotary tool device carried and applied by whole may be built upbefore being anus hand comprising a casing. an electric motor mounted insaid casing, said motor including a field magnet and a commutatorarmature, a chuck shaft journalled in said casing, a self-containedswitching unit removably mounted in a transverse bore or passage in saidcasing, said switching unit including a two-part casing of insulatingmateriaL'a movable switch member, an operating member to the outside ofthe casing and fixed contacts engageable by said switch member,cooperating contacts on said switching unit and in the casing, saidcooperating contacts engaging mutually by spring pressure, brush holdersin said casing, one of said brush holders engaging a groove in theswitching unit to hold the latter in place, and brushes mounted in saidbrush holders.

6. A rotary tool device carried and applied by hand, comprising acasing, a field magnet and winding in said casing, contacts associatedwith the field magnet winding, an armature includ-v ing a commutator, achuck shaft, means for driving said chuck shaft by said armature, aselfcontained switching unit removably mounted in a transverse bore orpassage in the casing, contacts on said switching unit in resilientengagement with the contacts on the field magnet winding, said switchingunit being formed from a two-part housing of insulating materialincluding a movable switching element, a slidable op:

erating member therefor positioned to the out side of the casing, aspring between said operating member and said switching element, andfixed contacts cooperating with said switching element, brush holdersone of which is adapted to engage a groove in the switching unit, afurther contact on the latter engaging the said brush holder, andbrushes in said holders pressed resiliently against the commutator.

7. In a portable electric tool of the character described, an outercasing, a horseshoe type motor therein, a control switch for the motor,said switch device being removably mounted in the casing adjacent thefield coil of the motor, and cooperating contacts on the switch deviceand the coil, respectively, said contacts having surface engagement forelectrically connecting the switch device and the coil when the switchdevice has been inserted in the casing and the parts have beenpositioned in operative relation.

8. In a portable electric tool of the character described, an outercasing, a horseshoe type motor therein, a control switch for the motor,said switch device being removably mounted in the casing adjacent thefield coil of the motor, and cooperating contacts on the switch deviceand the coil, respectively, said contacts having sur-- face engagement,one of said contacts being in the form of a strip extending in thedirection of movement of the switch device into the outer casing forelectrically connecting the coil and the switch device when the switchdevice has been inserted in the casing and the parts have beenpositioned in operative relation.

9. In a portable electric hand tool of the character described, an outercasing, a grip handle at the rear end of the casing and extending belowthe same, a horseshoe type-motor located in the casing forward of thehandle with the armature of the motor in the lower part of the casingand the field coil of the motor in the upper part of the casing, acontrol switch for the motor, said switch device being slidably mountedin the casing above the armature between the handle and the rear end ofthe field coil, and

cooperating contacts on the switch device and the coil, respectively,for electrically connecting the switch device to the coil when theswitch device has been inserted in the casing and the parts have beenpositioned in operative relation.

10. In a hand drill oi the character described, an outer casing, anelectric motor of the horseshoe type located in said casing and arrangedwith its armature in the lower portion of the casing and its field coilin the upper portion of the casing, a hollow handle at the rear end ofthe casing, upper and lower brush holders and brushes therein for themotor, the lower brush holder being located in the handle and the upperbrush holder being located. in the casing above the handle and in spacedrelation to the field coil, a support in the casing for the upper brushholder, said coil having an electrical contact surface facing saidsupport, and a manually operable switch device for the motor, saidswitch device being removably mounted in the casing between the upperbrush holder support and the field coil and having yieldable contacts onits opposite sides to respectively engage the upper brush holder and thefield coil contact surface when the switch device is in operativeposition in the casing.

11. In a hand drill of the character described, an outer casing, anelectric motor of the horse- 'shoe type located in said casing andarranged with its armature in the lower portion of the casing, and itsfield coil in the upper portion of the casing, a hollow handle at therear end of the casing, upper and lower brush holders and brushestherein for the motor, the lower brush holder being located in thehandle and the upper brush holder being located in the casing above thehandle and in spaced relation to the field coil, a support in the casingfor the upper brush holder, said coil having an electrical contactsurface facing said support, and a manually operable switch device forthe motor, said switch device being removably mounted in the casingbetween the upper brush holder support and the field coil and havingcontacts on its opposite sides for electrical connection with the upperbrush holder and the field coil contact surface, respectively, saidswitch device including a casing composed of a pair of substantiallymating sections, each provided with one of the switch contacts.

12. In a hand drill of the character described, an outer casing, anelectric motor of the horseshoe type located in said casing and arrangedwith its armature in the lower portion of the casing and its field coilin the upper portion of the casing, a hollow handle at the rear end ofthe casing, upper and lower brush holders and brushes therein for themotor, the lower'brush holder being located in the handle and the upperbrush holder being located in the casing above the handle and in. spacedrelation to the field coil, a support in the casing for the upper brushholder, said coil having an electrical contact surface facing saidsupport, and a manually operable switch device. for the motor, saidswitch device being removably mounted in the casing between the upperbrush holder support and the field coil and having yieldable contactsfor connecting the switch device with the upper brush holder and thefield coil contact surface, respectively, when the switch device is inoperative position in the casing, said switch device having channels inits opposite sides for the respective switch contacts, one channel beingdeep enough to have the upper brush holder interflt therewith, and theother channel being shallower so that the switch contact in said channelmay project beyond the same to engage the field coil contact surface.

13. In a hand drill of the character described,

an outer casing, an electric motoroi' the horseshoe type located in saidcasing and arranged with its armature in the lower portion of the casingand its fleld coil in the upper portion of the casing, a hollow handleat the rear end of the casing, upper and lower brush holder and brushestherein tor the motor. the lower brush holder being located in thehandle and the upper brush holder being located in the casing above thehandle and in spaced relation to the anus field coil, a support in thecasing for the upper brush holder, said field coil having an electricalcontact surface facing said support, and a manually operable switchdevice for the motor, said switch device being removably mounted in thecasing between the upper brush holder support and the field coil andhaving yieldable contacts on its opposite sides to respectively engagethe upper brush holder and the fleld coil contact surface when theswitch device is in operative position in the casing, said switch devicehaving a casing composed of a pair of separable overlapping sections,and a fastening element for securing the sections in assembled relation.

CHARLES DESOU'I'IER.

